Some keys of a conventional keyboard, such as a space key, are generally of an extended, long strip configuration. Therefore, a balance device is necessary for such keys. As shown in FIG. 3, a prior art balance rod 71 is pivotally arranged within a support assembly for a space key 7. One end of the balance rod 71 is pivotally connected at a front side of the space key 7. The balance rod 71 extends in angled orientation, with its other end pivotally connected to the base plate 72 of the keyboard. When the finger of a user presses at the side of the space key 7 which is pivotally connected to the balance rod 71, the pressing force is uniformly applied over the key. However, when the user's finger presses at the side of the space key 7 not connected to the balance rod 71, the pressing force is not uniformly applied over the key. Consequently, the key stroke operation may not be performed effectively. This problem is heightened in notebook type computers, the keys of which are arranged in more compact manner.
It is the object of the present invention to provide a balance device for a key, which has two balance rods having pivoting pole portions arranged, respectively, to extend adjacent the front and back edges of a key cap and supporting pole portions arranged in crossed manner. By use of the balance device, the key cap may be uniformly depressed, no matter where on the key cap the pressing force is applied.